The present invention is related to a method for commonly using scanning/printing path of a multifunction office machine and a device thereof. The device includes a common feeding power source which can be switched in operation direction as necessary for transferring documents to be scanned or sheets to be printed.
A conventional office machine with scanning and printing functions is generally designed with separated printing module and scanning module. The printing module and the scanning module respectively have different sheets/documents packing paths and feeding mechanisms. In fact, the parts of these two modules have the same function. Therefore, duplicate parts are used in the office machine. This leads to higher cost and is not economic. In addition, the volume of the office machine is enlarged so that the product of the office machine can be hardly minified and compacted.
U.S. Pat. No. 5,727,890 discloses a multiple-function printer with common chassis feeder/output path mechanisms and method of operation. The printer has a common sheets/documents feeding mechanism. As shown in FIG. 1 of the above Patent, a common input feeder slot 30 is obliquely arranged in a frame 20. The feeder slot 30 has an opening. A pick roller 32 is positioned beside an inner end (lower end) of the feeder slot 30. A divider 35 is disposed in the feeder slot 30 to divide the internal space thereof into an automatic document feeder ADF 28 and an automatic sheet feeder ASF 26. A pressure plate 34 is arranged on the bottom face of the feeder slot 30. One end of the pressure plate is pivotally connected with one side of the opening, while the other end of the pressure plate is supported on a spring 38. A stripper pad 33 is disposed beside the pick roller 32 to resiliently abut against the same. Further referring to FIGS. 8, 9 and 10 of the above Patent, the spring supports the pressure plate to different extents, whereby the documents in the automatic document feeder and the sheets in the automatic sheet feeder respectively contact with the surface of the stripper pad in different positions. The pick roller respectively drives the documents and the sheets to go between the pick roller and the stripper pad at different times. Accordingly, the printer has a common documents/sheets transferring mechanism. However, in actual operation, the above Patent has some shortcomings as follows:                1. Beside the pick roller, the documents in the automatic document feeder and the sheets in the automatic sheet feeder overlap each other (not totally separated). The pressure plate is supported by the spring to different extents so as to place the documents and sheets in the true feeding position. Then the pick roller serves to drivingly feed the documents or sheets. Accordingly, the precision of the documents/sheets feeding operation is apt to be affected due to different circumferential factors, for example, friction of the surface of the sheets, the wearing of the pick roller, elastic failure, etc.        2. As shown in the figures of the Patent, the documents in the automatic document feeder are positioned between the sheets in the automatic sheet feeder and the pick roller. Therefore, in use, in case that a great amount of documents are fed and scanned, only after all the documents are scanned and sent out, the sheets in the automatic sheet feeder can be fed and printed. Accordingly, the circuit must be inbuilt with a memory of very great capacity for memorizing the contents of the documents. As a result, the cost of the printer is increased so that the competitive ability of the product is lowered.        